Along with the spread of a personal computer in recent years, there has been increasing operational and management costs for installing or upgrading an application software, and for doing maintenance of hardware, etc. To address the reduction in the costs, thin client technology has been proposed.
FIG. 20 illustrates an explanatory diagram of a conventional thin client system. As illustrated in FIG. 20, a server 200 is coupled to a client personal computer (PC) 100 through Network Interface Cards (NIC) 110 and 120 that are communication units. The client PC 100 simply includes a keyboard, a mouse, a display, that is, a Video Graphics Array (VGA) display, a Central Processing Unit (CPU), and a memory. After the server 200 performs processing, the processing results by the server 200 are displayed on the client PC 100.
In the thin client system, the operation information in the client PC 100 is sent to the server 200 through the NIC 110 and 120. The server 200 includes a CPU, a memory, and a disk device. The server 200 executes a certain application, processes the operation information, and sends back the processing results to the client PC 100. The processing results sent from the server 200 are displayed on the client PC 100. The server 200 may be a real server or a server of a guest OS that is divided by a virtual machine.
In the thin client system, the client PC 100 is provided with the CPU and the memory because the keyboard, the mouse, the VGA display, and the NIC 110 in the client PC are generally processed. However, additional processing is performed little if not zero, so that a high-performance CPU and memory are not generally employed in the client PC.
Due to the thin client system, such additional processing is performed little if not zero, so that the install, update, or the like of application software to the client PC 100 may be omitted and a power-thrifty PC may be employed as the client PC 100. In addition, leakage of information may be reduced if not prevented because the client PC 100 does not hold data.
In the virtual machine system, the server (that is, a real machine system) 200 includes a virtual machine monitor (virtualization software), a host Operating System (OS), and two or more guest OS. The host OS is provided to manage the guest OS. The virtual machine monitor controls the host OS and the guest OS by virtualization technology.
The related systems are discussed as followed:
Patent Document 1, Japanese Patent Application Laid-open Publication No. 2008-052407 (for example, as illustrated in FIGS. 1 to 7 in the Publication);
Patent Document 2, Japanese Patent Application Laid-open Publication No. 11-134117; and
Non-Patent Document 1, “Thin client”, Incept Inc., Web site, Nov. 18, 1999, URL: http://e-words.jp/w/E382B7E383B3E382AFE383A9E382A4E382A2E383B3E38388.html, searched on Aug. 24, 2009.
In the conventional configuration, the thin client system may employ a power-thrifty PC, causing energy savings as a whole. However, in the conventional thin client system, the client PC generally includes the CPU and the memory because the processing capability to process the keyboard, the mouse, the VGA display, and the NIC 110 operations is desired in the client PC.
In the electricity consumption of the PC, it is generally said that the CPU consumes about 30% of the total electricity and the power source consumes about 40% of the total electricity. Thus the energy saving in the PC may be limited and the further reduction in the electricity consumption of the PC may be difficult. In addition, in the thin client system using two or more client PC in the office, etc., each of the client PC generally includes the CPU and memory, so that further cost reduction may be difficult.